Arrangement in a variable-crown roll provided with loading shoes

ABSTRACT

An arrangement of equipment in connection with a variable crown roll provided with loading shoes to prevent foaming of fluid. The arrangement includes a separate guide and a face that guides the fluid in order to guide the fluid smoothly away from the inner face of the roll mantle of the roll and into a collecting trough.

FIELD OF THE INVENTION

The invention concerns an arrangement for prevention of foaming of fluidin a variable-crown roll provided with loading shoes.

BACKGROUND OF THE INVENTION

Variable-crown rolls comprise a stationary axle inside the roll, onwhich axle the roll mantle is fitted to revolve. The roll mantle issupported in the press direction on the axle of the roll by means ofloading shoes acting upon the inner face of the roll mantle, which shoesare pressed against the inner face of the roll mantle by means of thepressure of a fluid.

In paper machines, rolls which form a dewatering press nip are usedcommonly. It is important that the distribution of the linear load, i.e.the profile, in the axial direction of the rolls can be made invariableand that the profile can be regulated in the desired way, for example,in view of controlling the cross-direction moisture profile and/orthickness profile of the web. Also in supercalenders, the aim is to beable to regulate the calendering nip in the axial direction of thecalender rolls so that the cross-direction thickness profile of the webbecomes as desired. For this purpose, from the prior art, a number ofdifferent variable-crown or adjustable-crown rolls are known, at whichattempts are made to act upon the distribution of the linear load in thenip.

In the rolls mentioned above, it has been noticed that foaming of thefluid is a drawback. The rolls comprise a central stationary axle, inwhich the loading shoes have been fitted, and the loading shoes projectfrom the axle so that their loading members reach contact with the innerface of the roll mantle. When fluid is sprayed onto the inner face ofthe roll mantle for the purpose of cooling, or when fluid enters ontothe inner face of the roll mantle through lubrication of the loadingshoes, the fluid strikes against said loading shoe constructions, inwhich connection the fluid is atomized and is then readily mixed withair. Great changes in the direction of the fluid cause so-calledwhipping, which further affects the fluid detrimentally and foams it, inwhich case the fluid must already be replaced after a short period ofuse. The operation of the hydraulic components of the system isdisturbed and their service life becomes shorter.

OBJECTS AND SUMMARY OF THE INVENTION

In the present application, a novel arrangement is suggested forelimination of the drawback mentioned above. In an embodiment of theapplication, it is suggested that a separate fluid guide is employed,which is fitted to be attached to the displaceable loading shoe by meansof an arm. By means of a spring, the guide is pressed into contact withthe inner face of the roll mantle. The guide comprises a gently curvedface, by whose means the fluid is guided to fall back into a fluidcollecting trough before it meets the side face of the loading shoe.Since the guide is attached to the displaceable loading shoe, the guidealways follows the shape of the roll mantle and is, thus, in contactwith the inner face of the roll mantle in a controlled way irrespectiveof any deformations of the roll mantle.

In a second preferred embodiment of the invention, a guide is used whichcomprises a separate loading member, for example a piston operating withfluid pressure, at whose end the guide is fitted. In such a case, thefluid pressure is fitted to be effective at the other side of thepiston, and by means of the fluid pressure the guide is kept in contactwith the inner face of the roll mantle.

In a third embodiment of the invention, the guide is provided with athrough opening, in which connection, by means of a curved face of theguide, the fluid is guided from the inner face of the roll into thethrough opening and further to fall down into the fluid collectingtrough. Also in this embodiment, a separate actuator acts upon theguide, which actuator can be a hydraulic piston actuator, or it can alsobe a spring actuator, by whose means the guide is kept in contact withthe inner face of the roll mantle in connection with any deformations ofthe roll mantle. Through the through opening in the guide, the doctoredfluid can flow through the guide and fall into the fluid collectingtrough by the effect of gravity. The embodiment is in particularsuitable for press constructions in which the loading shoes are in alower position.

The invention is characterized in what is stated in the patent claims.

The invention will be described in the following with reference to somepreferred embodiments of the invention illustrated in the figures in theaccompanying drawings, the invention being, yet, not supposed to beconfined to said embodiments alone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a prior-art solution, in which the fluid is guided to flowtowards the side by means of an inclined face structure of the shoes.

FIG. 2 shows a solution in accordance with the present invention, inwhich striking of the fluid applied to the inner face of the roll mantleagainst the inner face of the loading shoe is prevented so that thestationary central axle of the roll is provided with a separate fluidguide which extends substantially over the entire length of the roll.

FIG. 3A is a side view of the construction shown in FIG. 2.

FIG. 3B is an axonometric illustration in part of the construction shownin FIGS. 2 and 3A.

FIG. 3C is an axonometric illustration in part of an embodiment of theconstruction of a guide.

FIG. 4 shows an embodiment of the invention in which the guide isconnected with the displaceable loading shoe by means of an arm and aspring.

FIG. 5A shows an embodiment of the invention in which the press nip isplaced at the bottom in the roll and in which the guide is fitted, bymeans of a spring member and a shaft, in connection with the stationaryaxle so that, by means of the spring member, the guide is pressed intocontact with the inner face of the roll mantle, which guide comprises,in this embodiment of the invention, a flow opening passing through theguide so as to pass the fluid into the fluid collecting trough placedunderneath.

FIG. 5B shows a second mode of suspension of the guide shown in FIG. 5A.

FIG. 5C shows the fastening of the guide shown in FIG. 4 by means of aleaf spring to the piston.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a prior-art solution for prevention of foaming of fluid. Inan earlier solution of the applicant, the side faces of the loadingshoes 20 have been made inclined so that the fluid can flow towards thesides and further through the gaps between the loading shoes. In thesolution, the roll 10 comprises a stationary axle 12, from which theloading shoes 20 project. The roll mantle 11 is fitted to revolve onsupport of bearing means 14.

FIG. 2 shows a solution in accordance with the invention, in which,before the loading shoes 20, a fluid guide 13 has been fitted inconnection with the inner face of the roll mantle 11, which guide 13extends over the entire length of the roll and by means of which guidethe fluid is guided to fall directly into the fluid collecting trough.The guide 13 does not have to be made of one piece, but it may consistof a number of parts or pieces.

FIG. 3A is a side view of the solution shown in FIG. 2. The guide 13comprises loading means 15, by which the guide 13 is supported on thecentral axle 12 and by whose means the guide 13 is further pressedagainst the inner face of the roll mantle. The loading means 15 comprisea piston part 16 and a fluid space 17 placed in the stationary axle,into which fluid space the pressurized fluid is introduced, in whichconnection the fluid acts upon the piston 16. Then, by means of thefluid pressure, the guide 13 is pressed against the inner face of theroll mantle. As is shown in the figure, the cross-sectional shape of theguide 13 is a construction that includes a curved guide face 13 a, bymeans of which guide face, in the way shown in the figure, the fluid ismade to flow smoothly away from the connection with the roll mantle andfitted to fall into the fluid collecting trough 19. In the figures, theguiding of the fluid by means of the guide 13 is denoted with the arrowsL₁. The sense of rotation of the roll mantle is denoted with the arrowS₁.

FIG. 3B is an axonometric view of the construction shown in FIG. 3A. Theguide is connected with a number of loading members 15 over its length,which members are piston devices in the embodiment shown in the figure.The guide may also be composed of separate parts or pieces, so that atleast two pistons or springs act upon each piece.

FIG. 3C illustrates an embodiment of the guide 13. As is shown in thefigure, the face 13′ of the guide that is placed against the roll mantlemay be provided with grooves U₁,U₂ . . . or with other ducts, by whosemeans the flow of a certain amount of fluid further is permitted, forexample, for purposes of cooling. The face 13′ may also be roughened insuch a way that a small amount of fluid can flow through the guide.

FIG. 4 shows a second embodiment of the invention, in which the guide 13is connected with the displaceable shoe portion 20 a of the loading shoe20 by means of a spindle 21 and a spring 22. In such a case, the guide13 always follows the movement of the loading shoe 20 a and is, thus, incontact with the inner face of the roll mantle while complying with alldeformations of the roll mantle produced by the loading shoe/shoes. Bymeans of the spring 22, the guide 13 is pressed into contact with theinner face of the roll mantle. The spring is compressed between thestationary axle 12 and the guide 13. The spiral spring 22 is fittedaround the spindle 21. The spindle 21 is fitted with a glide fitting inthe hole n in the side face of the loading shoe 20, so that it can bedisplaced in a way similar to a slide.

FIG. 5A shows an embodiment of the invention in which the loading shoesare placed in the lower position. In the embodiment of the invention,the guide 13 includes a central flow opening 23, which permits fallingof the fluid, after separation of the fluid, through the guide into thecollecting trough 19 placed underneath. In this embodiment, the guide ispressed with spring force by means of the spring 24 against the innerface of the roll mantle, while the guide 13 is attached to thestationary axle 12 by means of the spindle 25 and while the spring 24 isfitted around the spindle 25 between the stationary axle 12 and theguide 13. The spindle 25 is fitted in the hole (n) in the axle 12 bymeans of a glide fitting, in which connection the spindle 25 receivesits control and can be displaced into different positions in compliancewith any deformations of the roll mantle.

FIG. 5B shows a second mode of suspension of the guide 13 shown in FIG.5A. The guide 13 is suspended on the axle 12 so that the guide 13 isconnected with a spindle 21, which is guided in through openings e₁ ande₂ in the suspension brackets p₁ and p₂. The spindle 21 is connectedwith a flange plate d, and the spring 22 is fitted as compressed betweenthe bracket p₂ and the flange plate d around the spindle 21. Thus, thespring 22 presses the flange d, which, being fixed to the spindle 21,further presses the spindle 21 and the connected guide 13 towards theinner mantle 11′ of the roll 11.

FIG. 5C shows a second mode of suspension of the guide 13 as shown inFIG. 4 on the piston 20. In the embodiment of FIG. 5C, the guide 13 hasbeen suspended by means of a leaf spring 220. The leaf spring 220 is aresilient, flexible construction element, which is fixed both to thepiston 20 and to the guide 13, and by its means the guide 13 is pressedagainst the inner face 11′ of the roll mantle. A similar mode ofsuspension can also be applied to the guide 13 shown in FIGS. 5A and 5B.

What is claimed is:
 1. An arrangement of equipment in connection with avariable-crown roll provided with loading shoes for the prevention offoaming of fluid, characterized in that the arrangement of equipmentcomprises a separate guide (13) and therein a face (13 a) that guidesthe fluid smoothly away from the inner face (11′) of the roll mantle(11) and into a collecting trough (19), in which arrangement ofequipment the guide (13) has been fitted separate from the loading shoes(20).
 2. An arrangement of equipment as claimed in claim 1,characterized in that the guide (13) comprises a curved face (13 a), bywhose means the fluid is guided smoothly apart from the inner face ofthe roll mantle to fall further into the fluid collecting trough (19),and that the guide (13) extends substantially over the entire length ofthe roll (11) and consists of one or several separate parts.
 3. Anarrangement of equipment as claimed in claim 1, characterized in that,between the guide (13) and the stationary axle (12), there is a separateactuator (15;22;220).
 4. An arrangement of equipment as claimed in thepreceding claim, characterized in that the stationary axle (12) includesa piston device (16,17), by whose means the guide (13) is pressed intocontact with the inner face (11′) of the roll mantle.
 5. An arrangementof equipment as claimed in the preceding claim, characterized in thatthe fluid space (17) of the piston device has been formed into thestationary axle (12), and the piston (16) has been fitted into saidfluid space (17), and further the piston (16) is coupled with the guide(13).
 6. An arrangement of equipment as claimed in claim 1,characterized in that there is a separate spring (22;220), by whosemeans the guide (13) is pressed into contact with the inner face (11′)of the roll mantle.
 7. An arrangement of equipment as claimed in thepreceding claim, characterized in that the spring (22,24) has beenfitted around the spindle (21,25), which spindle (21,25) is fitted bymeans of a glide fitting in the hole (n) in the stationary axle (12) orin the loading shoe (20), in which connection the spindle (21,25) can bedisplaced in a way similar to a slide, and in which connection thespring (22,24), when it acts between the guide (13) and the stationaryaxle (12) or between the guide (13) and the loading shoe (20), pressesthe guide (13) into contact with the inner face (11′) of the rollmantle.
 8. An arrangement of equipment as claimed in the precedingclaim, characterized in that the spindle (21) has been fitted inconnection with the side face of the displaceable loading shoe (20), inwhich connection the guide (13) coupled with the spindle (21) alwaysfollows the deformations of the roll mantle produced by the loading shoe(20).
 9. An arrangement of equipment as claimed in claim 1,characterized in that the guide (13) includes a through opening (23), inwhich case the guide (13) can also be fitted in such press positions inwhich the loading shoes (20) in the roll (11) are placed in a lowerposition, and in which case, by means of the guide (13), the fluid isfirst guided apart from the inner face (11′) of the roll mantle andfurther, through the opening (23) passing through the guide, to fall bythe effect of gravity into the collecting trough (19) placed underneath.10. An arrangement of equipment as claimed in claim 1, characterized inthat the guide (13) is a rib-like part which doctors the fluid and whichhas been fitted substantially over the entire length of the roll, andthat there are several loading means acting upon the guide, such assprings (22) or pistons (16), fitted across the length of the roll (11).11. An arrangement in a variable-crown roll having loading shoes, astationary axle from which the loading shoes project and bearing meanssupporting the roll from an inner face of a roll mantle, the arrangementcomprising: a fluid guide structured and arranged in connection with theinner face of the roll mantle, said fluid guide having a face portionthereon, a trough located substantially beneath said fluid guide, saidface portion of said fluid guide structured and arranged to guide afluid away from the inner face of the roll mantle and into said trough.12. The arrangement according to claim 11 wherein said guide extendssubstantially over the entire length of the roll and wherein said faceof said fluid guide is curved.
 13. The arrangement according to claim 11further comprising loading means for pressing said fluid guide againstthe inner face of the roll mantle.
 14. The arrangement according toclaim 11, wherein said fluid guide is supported by the stationary axle.15. The arrangement according to claim 13, wherein said loading meanscomprise a piston device having a fluid space and a piston part, saidfluid space located within the stationary axle and said piston partcoupled to said fluid guide wherein said fluid guide is pressed againstthe inner face of the roll mantle upon the introduction of a pressurizedfluid into said fluid space.
 16. The arrangement according to claim 13,wherein said loading means comprise a spindle and a spring fittedthereon, said spindle coupled to said fluid guide.
 17. The arrangementaccording to claim 16, wherein said spindle is coupled to the stationaryaxle.
 18. The arrangement according to claim 16, wherein said spindle iscoupled to the loading shoe.
 19. The arrangement according to claim 18,wherein said spindle is structured and arranged in connection with theloading shoe and said fluid guide wherein said fluid guide substantiallyfollows deformations in the roll mantle produced by the loading shoe.20. The arrangement according to claim 11, wherein said fluid guidefurther comprises a central flow opening wherein the fluid is firstguided apart from the inner face of the roll mantle and through thecentral flow opening passing through said fluid guide and directly intosaid trough.